"UNIFIL has launched an investigation to establish the circumstances of the incident, including the exact location where the man was apprehended," UNIFIL representative Neeraj Singh was quoted as saying by the Lebanese English-language newspaper the Daily Star. "The investigation is ongoing."

Rabih Mohammed Zahra was tending to a flock of sheep on Sunday in the Bastara Farm village near the disputed border area of Shebaa Farms when he was arrested by Israeli soldiers on Sunday, media reports say.

The Shebaa Farms, an area of roughly 10 square miles at the junction of southeastern Lebanon, southwestern Syria and northern Israel, has been occupied by the Jewish state since the 1967 Arab-Israeli war. It's been disputed turf ever since.

But a joint inspection conducted by the Lebanese army and UNIFIL concluded the shepherd was arrested on Lebanese territory, according to Lebanon's official National News Agency.

A statement by the Lebanese Foreign Ministry called the incident a "clear violation" of U.N. Security Council resolution 1701, which ended the July 2006 war between Israel and Hezbollah, and Lebanese territorial sovereignty.

After spending several hours in Israeli detention, Zahra was handed back to members of UNIFIL at its base in southern Lebanon on Monday morning and then given over to the Lebanese army.

A Lebanese army spokesman told Agence France Presse that Zahra had been beaten while in detainment, saying the shepherd came back with bruises on his face and neck.

Others media reports said Zahra had been interrogated by his Israeli captors about the activities of Hezbollah in the area.

Israeli media, meanwhile, reported that Zahra was carrying a weapon when he was apprehended by Israeli soldiers. The Israeli newspaper Haaretz reported that Israeli security forces had arrested " a shepherd carrying a commando knife."

Israel has previously arrested people in the disputed border area in southern Lebanon. In recent months, cattle also have crossed the border from one country to another. Last fall, Lebanese media reported that UNIFIL was working on plans to put up a fence in some areas in the Lebanese south to prevent Israeli cows from straying into Lebanon.